(a) Technical Field
The present invention relates to a method of forming a multilayer coating film made from a natural material. For example, the method may comprise forming a color coating film for providing adhesion and color to a cork of a substrate, and forming a clear coating film for providing texture and supplementing properties on the color coating film, thereby manufacturing the multilayer coating film on the substrate comprising the cork. As such, the multilayer coating film made from a natural material, e.g. cork, may diversify the color and gloss from a natural material (the cork), and additionally increase marketability of an interior material and provide various exteriors. In addition, the multilayer coating film may prevent discoloration due to light (e.g. UV light.) and water permeation, and enhance durability against abrasion, scratches, and the like.
(b) Background Art
Recently, materials including components containing real wood has been used to provide sophistication, luxuriousness, and the like to the exteriors of vehicles. For example, in the process of producing the interior materials containing the real wood, a base to be covered with a wood material is first laid as a base layer and then the base is covered with the real wood, followed by coating/polishing a surface of the real wood as a finishing process. Through the coating/polishing, the surface of the real wood becomes smooth and glossy and, at the same time, visual luxuriousness like wood grain may be obtained.
Cork typically provides excellent insulation, noise insulation, electric insulation, elasticity and the like with luxuriousness, which is one of the characteristics of a natural material. In addition, the cork removes superior volatile organic compounds (VOC), discharges far-infrared radiation, deodorizes, and has antibacterial function and the like. Accordingly, the cork has been used instead of conventional real wood materials.
However, such natural cork may be epidermis of a cork oak and a soft material, scratch resistance, abrasion resistance, and the like thereof may be weak. In addition, since natural cork is a wood material, it may be susceptible to discoloration by light or deformation by moisture.
Accordingly, when the natural cork is used under severe conditions as in vehicle components, a coating may be required to the surface of the natural cork. With regard to this surface-coating, there is a need for research into preventing discoloration of the natural cork due to light (e.g. UV light.) without surface luxuriousness decrease of the natural cork and enhancing durability such as scratch and abrasion resistance and gloss.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.